WO2010/034814 discloses a switching installation having a gas-filled and gastight enclosure. Inside the enclosure at least one input conductor is arranged, which carries an input voltage. This input voltage is typically in the range of medium to high voltages, i.e. 1 kV and higher. The input conductor is enveloped in a solid insulation to insulate the input conductor from the housing.
To reduce or prevent accidental internal arcing inside the housing, protection means are provided. These protection means have a short-circuit device changeable from a first condition to a second condition. In the first condition the short-circuit device is in a rest position, in which the insulation insulates the input conductor from the housing.
In this publication a solid insulation is used, but the input conductor could also be insulated by a vacuum or by other means. In the second condition, the short-circuit device creates an opening in the insulation, typically by puncturing or removing a part of the insulation, such that an electrical connection is created between the input conductor and an auxiliary connection, such as a ground point or another conducting part of the installation.
The short-circuit device is operated by a lever, which is hingedly attached to an internal frame of the switching installation and which lever is connected with a free end to a back wall of the housing. When internal arcing occurs, the pressure will rise inside of the housing, such that the back wall of the housing will bend outwardly and the connected lever will operate the short-circuit device.